#include <stdio.h>
#include <math.h>

int main(){
	float suma, novasuma=1, fakt=1, xn=1, x, eps;
	int i=1;
	scanf("%f %f", &x, &eps);
	
	do{
		suma = novasuma;
		xn*=x;
		fakt*=i;
		novasuma = novasuma + xn/fakt;
		i++;
	}while(fabs(suma-novasuma)>eps);

	printf("%.8f\n", suma);
	return 0;
}